Oil-switch.



" E. M. HEWLETT.

OIL SWITCH. APPLICATION FILED NOV. 7, 1904.

Patented 0ct.27,1908.

INVENTQFE Edv/ardMHev/Iett.

\A/THESSES UNITED STATES PATENT OFFICE.

EDWARD M. HEWLETT, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

OIL-SWITCH.

Specification of Letters Patent.

Patented Oct. 27, 1908.

Application filed November 7, 1904. Serial No. 231,667.

"To all whom it may concern: 1

-Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Oil- Switches, of which the following is a specification.

The present invention relates to electric switches of the oil break type employed in handling currents of high potential and large amperage, and the object of the invention is to provide a novel organization which shall be effective in rupturing circuits of this character.

In the present embodiment, the oil is maintained under pressure in a portion of the system and released to throw the switch and extinguish the arc. The latter function is performed by causing the oil to flowover the terminals of the separating electrodes in a continuous stream which continues until shut off by the operator. The oil after passing through the switch is collected in a suitable well and is pumped back to the starting point to be used over again.

For a better understanding ofthe invention reference should be had to the following detailed description taken in connection with the accompanying drawing which illustrates the switch in section connected up to the various parts of the system.

Referring indetailto the drawing, 10 des-,

' ignates. the switch casing which is composed of cylindrical end castings 11 and 12 and an intermediate insulating member 13 of cement, porcelain or other suitable material; The interior of the casing of the switch is divided into three compartments or ChfLll1-- bers by means of a fixed partition 14 and a movable abutment or partition 15. The partition 14 is formed integral with the end member 11 and the piston 15 is fitted into a cylindrical bore in the member 12 so as to be reciprocated therein. The partition 14 carries a tubular contact 16 which is rigidly secured thereto, and with which a similar" tubular contact 17, carried by and movable with the piston 15, cooperates. The contact 17 is provided with a removable tip 18 hav ing spring fingers which embrace the outer end of the tubular contact 16 so as to form good electrical engagement therewith. This tip is removable so that it maybe replaced in case it becomes necessary because of the destructive action of the current. In addition to 'the'contact tip 18 the piston 15, which is electrically and mechanically connected to the tube 17, is provided with an annular slitted contact 19 which embraces a contact ring 20 on the partition 11 of the end member 11. The annular contacts 18 and 19 are arranged so that as the electrodes separate the circuit is first broken between the primary contacts 19 and 20 and the final break occurs between the secondary contacts 18 and 16.

The interior of the switch casing lying between the partition 1st and the piston 15, which constitutes the central chamber, is supplied with oil or other insulating fluid from a reservoir 21 which is connected therewith by means of piping 22 and ports 23 and 24 in the member 11 of the casing. The outer chambers of the switch casing are connected by means of piping 25 and 26 to a discharge pipe27 which terminates in an oil well 28. The switch casing is completely insulated from the system of piping by means of the glass or porcelain insulators 29, 30 and 31. The supply of oil to the switch from the reservoir 21 is controlled by means of a valve 32 in the pipe This valve may be operated in any desired manner and I have shown it in the present instance controlled by an overload coil 33. This coil by drawing upward upon its armature 34 will throw the catch 35 out of engagement withthe lever 36 of the valve and to terminal 40 on the end member 12 of theswitcht'eas'ing, thence through said member, the piston 15, the primary and secondary switch contacts 18 and 16, 19 and 20 to the opposite end member 11 of the casing, and thence from the terminal 41, secured thereto, to line by way of the lead 42 and the overload coil 33. With this organization, with the switch closed as illustrated,,upon an eX- cessive current in the coil 33, the controlling valve 32 is opened and the oil under pressure in the reservoir 21 is admitted to the central chamber of the switch and acting upon the left of the piston 15 forces it to the right against the action of the spring 43. This as previously indicated first causes a separation of the contacts 19 and 20 and then the separation of the secondary contacts 16 and 18. As soon as the contacts 16 and 18 separate, oil will begin to flow through the tubes 16 and 17 into the outer chambers of the switch casing as indicated by the arrows. It is obvious that in opening the switch this flow of oil through the electrodes will begin before the piston 15 has reached the limit of its opening movement. In order therefore that the back pressure at the right of the piston may not interfere with its proper operation, it is necessary to regulate the flow of oil through the tube 17. This is accom plished in the present instance by an apertured diaphragm 44 located in the tube. It is obvious that the flow of oil through this tube may be varied by varying the size of the opening in the diaphragm; or it may be possible to omit thediaphragm altogether where the size of the tube is such as not to permit a flow that will be objectionable. The switch is held in its open position by means of a spring pressed latch 45 which engages the piston. ,Upon opening the switch the passage of oil into the tubes 16 and 17 produces a strong flow which tears apart the arc and carries away the conductlng gases and vapors into the outer chamber of the switch casing andthe gases are permitted to pass through the piping 25 and 26 to the vent 47 from which they may escape to atmosphere. When the circuit is thus ruptured the oil supply may be cut off by manually closing the controlling valve. 32. \Vhen this is done the oil in the switch casing will fall to the level indicated by the line When it is desired to close the switch the lever 16 may be pressed downward to disengage the catch 45. so as to tree the piston 15 and allow it to move to its closed position under the action of the compression spring 43.

Any desired means may be employed for conveying the oil from the well 28 to the res" ervoir 21 and maintaining it under pressure. In the present instance I have shown an elec trically driven pump 48 mounted above the oil well and communicating therewith by a pipe 49 and with the reservoir 21 by piping 50. The motor which drives the pump 48 is included in circuit with a suitable controlling switch 51 provided with a float 52 which rests upon the surface of the liquid in the reservoir; The switch 51 .is arranged so that when the level of the oil falls the circuit. through the motor will be completed and the pump thereby actuated to supply oil to the. reservoir.

The pump will continue to operate until the level of the liquid is again sufficient to open the switch.

It should be noted that with the switch organization which I have herein disclosed the pressure of oil in the circulating system is utilized to open the switch and at the same time extinguish the are by carrying away its gases and vapors and that the flow of oil through the electrodes may be continued any desired time as long as the switch remains open. 7

It is obvious that many changes may be made in the general organization here presented without departing from the spirit and scope of my invention. I therefore do not wish to be limited to the specific matter disclosed but aim to cover all equivalents by the terms of the appended claims.

What I claim as new, and desire to secure by Letters Patent of the United States, is,

1. The combination with an electric switch, of a circulating oil system compris ing a reservoir, a pump for storing oil under pressure in said reservoir, means for admitting oil under pressure from said reservoir to said switch, actuating mechanism operated by oil under pressure to open the switch and permit the oil to extinguish the arc produced, and a discharge pipe for returning oil from the switch to the pump.

2. The combination with an electric switch, of a circulating oil system comprising a system of piping, a pump for supplying Oll under pressure to a portion of said system, means for admitting oil under pressure from said portion of said system to the switch, actuating means operated by oil under pressure to open the switch and permit the oil to fiow under pressure against the are produced by the opening of the switch, and a discharge pipe for returning the oil from the switch to said pump.-

3. An electric switch comprising a casing containing oil, a partition therein, means connected with opposite sides of said partition for conducting the oil from one side and supplying it under pressure to the other side, and separable electrodes within said casing .providingupon separation a communicating passage between the opposite sides of said partition.

4. An electric switch comprising a casing containing oil, 'a partition therein, means connected with opposite sides of said partition for conducting the oil from one side and supplying it under pressure to the other side, and separable electrodes within said casing, one of said electrodes being provided with an opening therethrough communicat-' ing between the opposite sides of said partition.

5. An electric switch comprising a casing containing oil, a movable abutment therein,

means connected with opposite sides of said abutment for conducting oil from one side and supplying it under pressure to the other side, and separable electrodes actuated by said abutment and arranged to provide upon separation a communicating passage between its opposite sides.

(3. An electric switch comprising a casing containing 011, a movable abutment therein,

sure to the central compartment, and separable electrodes. within said casing arranged upon separation to establish communication between the central and outer compartments.

8. An electric switch comprising a casing containing oil, two-partitions therein dividing the casing into three compartments,

. means for conducting the oil from the outer compartments and supplying it under pressure to thecentral compartment,-and tubupartment and communicating between said compartment and the-outer compartments.

9. An electric switch comprising a casing containing oil, a partition and a movable abutmeii-t therein dividing the casing into three compartments, means for conducting the oil from the outer compartments and lar electrodes separable in the central comsupplying it under pressure'to the central compartment, a tubular electrode communicating between opposite sides of said partition, and a cooperating movable electrode carried by said abutment and communicating with the opposite sides thereof.

In witness whereof I have hereunto set my hand this 4th day of November, 1904. i EDVARD M: HEVVIJETT. \Vitnesses: v a

. BENJAMIN B. HULL,

HELEN Onronn. 

